The Brain and Drugs

The Brain and Drugs

The brain is a complex structure made up of billions of nerve cells called neurons. These neurons communicate with each other through chemicals called neurotransmitters. The brain is also involved in the perception of emotions such as pleasure, sorrow, anger, reward, punishment, etc. Drugs interact with the neurotransmitters, thereby, altering the perceptions of human emotions.

The most important emotion involved in the sustenance of life is pleasure. The commonly used drugs act by stimulating the pleasure sensations and as a result, people who are addicted to drugs, want to experience the same sensation again and again. Some of the most prominently abused drugs are mentioned below.


Marijuana is obtained from dried leaves and flowers of Cannabis sativa. The active ingredient in marijuana is tetrahydrocannabinol (THC). People using marijuana experience a feeling of euphoria; a feeling of extreme happiness. It impairs a person’s judgment, slows reaction time and the ability to drive, Regular use of marijuana impairs memory and leads to a decline in academic performance.


Opiates are powerful drugs obtained from poppy plants, commonly used for pain relief. Common drugs in this category include morphine and codeine. Heroin is the most common drug abused in this group. Heroin is rapidly absorbed and reaches the brain through the bloodstream. Once there, it stimulates opiate receptors, resulting in feelings of reward and pleasure.

This leads to a short period of euphoria, followed by a few hours of being in a relaxed, contended state. Continued use of heroin can lead to addiction. These opiates also suppress the breathing centre in the brain. Overdose of heroin can shut down this respiratory centre leading to stoppage of breathing and death.

MDMA (Ecstasy)

MDMA or popularly known as ecstasy leads to an excess release of the neurotransmitter, serotonin, causing mood elevation. However, prolonged use of MDMA leads to depletion of serotonin, contributing to negative behavioural effects, seen after several days of taking MDMA.

Symptoms may include anxiety, confusion, depression, sleep problems, impairment of working memory and impaired attention. MDMA also has adverse effects on the development of a foetus’s brain if pregnant women abuse this drug.

Anabolic steroids

Anabolic steroids are similar to testosterone and are commonly used by youngsters for building/enhancing muscle mass. Anabolic steroids can be either abused orally or through injections. In the brain, steroids are mainly distributed to the hypothalamus and limbic system.

Steroids can impair learning and memory. They can also promote aggressive behaviour and mood swings. People abusing anabolic steroids may show violent behaviour, impaired judgment and psychotic symptoms.

The commonly used drugs act by stimulating the pleasure sensations and as a result, people who are addicted to drugs, want to experience the same sensation again and again


Cocaine acts on the pleasure circuit to prevent reabsorption of dopamine leading to build-up of dopamine in a synapse structure, which causes strong feelings of pleasure and euphoria. Cocaine use impairs memory and learning, especially the emotional aspects of memory. It can also cause the constriction of blood vessels in the brain, leading to stroke (paralysis of arms and legs).

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